As preachers we are given authority by the people who have called us to preach God's word to them. If, however, we don't speak with authority, having listened for God so that we might speak his word, we are those false prophets whom Moses promises "will surely die."
That authority things is delicate. The scribes, who we hear didn't preach with authority like Jesus preached with authority, spend the next three years angry that Jesus is trying to take their power away. How often do we do the same thing? Isn't it the key interest of those with power to keep things the way they are, lest they lose their power? Do we as preachers tread into that dangerous water? How do we hold loosely onto our authority? First, and foremost, we recognize that any authority we might seem to hold is only the authority of one greater than us. Hold onto it loosely, lest it be removed by force.